ep4000 bridge mono mode ( have i been running this wrong all this time )

ep4000 bridge mono mode ( have i been running this wrong all this time )

Don't think i'm nuts for asking this.
using ep4000 in bridge mono mode. Two 18"subs in parallel for a 4 ohm load.
output channel one with speakon cable +1 +2 to subs ( +2 -2 ) thru ( +2 -2 )
here is where my question comes into play. the mode switches say 6 & 7 should be on for bridge mode but when i do this amp has no output and red clip light channel one is on all the time.